Soaring

Soaring is an extraordinary form of engineless flight (free flight.)  In the summer months, convection of the atmosphere produces large motion of the air (thermals) which moves the warm air from the surface to the cooler thermal reservoir at higher altitudes.  It is not unusual in the Sierra for the thermals to reach over 18,000'.  By circling in the rising air (lift) and flying quickly through the downdrafts (sink), it is possible to remain aloft all day and cover hundreds of kilometers. 

In the winter months, high speed winds over the Sierra escarpment can produce an incredible form of lift called mountain lee wave.  This lift is aligned parallel to the mountain range and can extend to very high altitude.  This effect can produce glassy smooth and very rapid lift (>1km/min) above the ridge height, and the most extreme turbulence known below the ridge; gliders have been destroyed in this turbulence with loads exceeding 10g's.   Glider pilots have used this lift to achieve altitudes of 49,000' in the Owens Valley.   "Flying the wave" is an opportunity to experience the raw and unforgiving power of nature, and is extremely interesting and challenging. 

Video above:  15,000' over the Sierra, late afternoon, heading south to Mt. Whitney (July 2020).    The videos have been taken with a GoPro Hero 8 attached to the horizontal stabilizer. 

Modern gliders are very beautiful and extremely efficient.  Glide ratio of 40-50:1 are typical (flying 40-50km forward for every 1km of descent.)  Photo above is N303DG over the White Mountains, with a wingspan of 15m, a best glide of 42:1, and an empty weight of 270kg .